The present invention relates to the field of dynamic magnetic information storage or retrieval. More particularly, the present invention relates to the field of magnetic tape heads. In still greater particularity, the present invention relates to magnetic tape head modules. By way of further characterization, but not by way of limitation thereto, the present invention relates to a module of a tape head assembly having adjacent substrates in which each substrate includes write and/or read elements.
In magnetic recording technology it is constantly desired to improve the areal density at which information can be recorded and read. This desire has lead a trend toward shrinking track widths of a magnetic media such as tape. A tape drive having a head assembly is used to write and read data to and from magnetic tape. The head assembly includes modules connected together. Each module has a substrate of active elements such as write and read elements. Typically, a mechanical closure piece is bonded over the substrate for each module.
In order to record and read data to and from magnetic tape having closely spaced tracks, the head assembly will need to have more tracks per inch (TPI) in the head, i.e., more write and read elements per unit length, and smaller gap to gap spacings between the elements to reduce the effects of media deformation and read/write alignment on track mis-registration. Efforts to increase TPI at the wafer level lead to vastly increased complexity on the wafer build process and subsequent yield loss. Efforts to decrease gap to gap spacing by reducing substrate and closure thickness result in an increased fragility of the head assembly and subsequent yield loss. These requirements can be addressed by using an adjacent substrate assembly process for a head assembly in which a substrate of active elements is used in place of the mechanical closure piece that is typically used in the head assembly.
Accordingly, it is an object of the present invention to provide a tape head module having adjacent substrates in which each substrate includes write and/or read elements.
It is another object of the present invention to provide a tape head module having adjacent substrates in which each substrate includes write elements.
It is a further object of the present invention to provide a tape head module having adjacent substrates in which each substrate includes read elements.
It is still another object of the present invention to provide a tape head module having adjacent substrates in which one substrate includes write elements and the other substrate includes read elements.
It is still a further object of the present invention to provide a tape head module having adjacent substrates in which one substrate includes a combination of write and/or read elements and the other substrate includes a complimentary combination of write and/or read elements.
It is yet another object of the present invention to provide a tape head module having adjacent substrates in which each substrate includes horizontal and vertical alignment marks to enable the adjacent substrates to be properly aligned with respect to one another.
It is yet a further object of the present invention to provide a tape head module having adjacent substrates each provided with substrate pads for connecting the active elements of the substrates to the external environment in which the substrate pads are offset with one another.
In carrying out the above objects and other objects, the present invention provides a module for a tape head assembly including a first substrate having active elements and a second substrate having active elements. The second substrate is positioned over the first substrate. In one embodiment, the first substrate has a row of spaced apart write elements and the second substrate has a row of spaced apart write elements. The write elements of the first substrate are aligned between the write elements of the second substrate when the second substrate is positioned over the first substrate. In another embodiment, the first substrate has a row of spaced apart read elements and the second substrate has a row of spaced apart read elements. The read elements of the first substrate are aligned between the read elements of the second substrate when the second substrate is positioned over the first substrate. In a further embodiment, the first substrate has a row of write elements and the second substrate has a row of read elements. The write elements of the first substrate are aligned directly across with the read elements of the second substrate when the second substrate is positioned over the first substrate.
Preferably, the first and second substrates have front surfaces with the active elements of the first and second substrates located on the front surfaces of the first and second substrates. The front surfaces of the first and second substrates face each other when the second substrate is positioned over the first substrate. The front surfaces of the first and second substrates each include a set of substrate pads and conductive leads. Each conductive lead connects an active element to a corresponding substrate pad. The substrate pads connect the active elements to an external device. Each set of substrate pads are positioned on one side of the substrates such that each set of substrate pads are offset with respect to one another when the second substrate is positioned over the first substrate. Each substrate includes a window on the other side of the substrates for exposing the offset substrate pads when the second substrate is positioned over the first substrate.
Preferably, the first and second substrates include horizontal alignment marks for horizontally aligning the first and second substrates when the second substrate is positioned over the first substrate. The horizontal alignment marks are referenced with respect to the active elements. Preferably, the first and second substrates include vertical alignment marks for vertically aligning the first and second substrates when the second substrate is positioned over the first substrate. The vertical alignment marks are referenced with respect to the active elements.
In carrying out the above objects and other objects, the present invention further provides a method for assembling the module of the tape head assembly of the present invention.
The above objects and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the present invention when taken in connection with the accompanying drawings.